dermatology cases

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Atopic dermatitis (eczema)

Adolescent with asthma presents with:
long standing intermittent, pruritic, papulosquamous eruption over antecubital fossa, behind knees; worse after hot showers

Seborrheic dermatitis
Can also present on eyebrows, lashes, facial hair
HIV can have a much worse presentation; Due to a lipophilic yeast in skin called Pityrosporum ovale and can be tx with ketoconazole cream, ciclopirox gel or low potency topical steroid.

Adult pt with:
"dandruff" and scaly rash around the nose with underlying redness when the scales are removed

Contact dermatitis
Common triggers: plants (poison ivy, oak), nickle, perfumes, rubber, synthetic shoe materials

Pt develops:
Itchy, papulosquamous rash on abdomen- scaly, well circumscribed lesion at the area of the belt buckle

Rosacea
Keys: lack of comedones, worse with alcohol, telangiectasias

Middle-aged female develops:
"Acne" on the cheeks
Repeated eruptions of facial flushing and erythematous papular lesions, made worse with alcohol intake
Multiple small papules on the cheeks without comedones
Scattered telangiectasias

Hidradentis suppurativa
DDx- boils (furuncles, not symmetric, get central necrosis), acne conglobata (not in axilla)

Female presents with:
Pain under both axilla x 2 mo- began as small bumps but getting larger
Significant pain and erythema around the bumps x 24 hrs
Deep, nodular lesions in both axilla without any cental area of necrosis
Few comedones in the axilla

Hairy Leukoplakia
Caused by EBV
DDx- thrush- whole mouth, can be removed with red undersurface

Pt with:
Wt. loss x 3 mo
Intermittent fevers
Bilateral white plaques on the lateral aspect of the tongue that cannot be removed with a tongue depressor
+ HIV ELISA, Western Blot

Geographic tongue-yellowish or looks like patchs of "missing tongue"; Only tongue condition that is migratory (changes position)

Pt with:Intermittent mild pain and burning on the tongue
Variable, raised, yellow pattern on the tongue that changes position

Fixed drug eruption
Same rash every time
Frequently in the genital region

Pt prescribed Doxycycline for rx of pneumonia, after 3 days develops:
Large erythematous annular plaque in the genital region
Had same rash as teen when given Doxy for acne
Resolves with DC of Abx

Psoriasis
Assc with spondyloarthropathies

20's y/o with:
Bilateral itchy, erythematous plaques in knees, elbows that develop an adherant silvery scale that bleeds when removed
Similar plaques on the scalp
multiple tiny pits in some of the nail beds

Erythema nodosum
Bilateral painful nodules over shins= E. nodosum!
Assc. with GAS pharyngitis, Coccidiodes, Histoplasmosis, TB, sarcoidosis (with hilar adenopathy), IBD (with abd pain)
75% idiopathic

Previously healthy female with:
Fever
Sore throat
3 wks painful, erythematous nodules on shins-> bruises

Pyoderma gangrenosum
Keys: UC, neutrophilic infiltrate; Assoc with IBD (crohn's and UC); May also be assoc with RA. Usually has a violaceous hue.

Pt with active ulcerative colitis presents with:
Pretibial sore, began as erythematous pustule->nodular->ulcer, ragged with purple raised border
Skin bx- tissue necrosis with neutrophilic infiltrate
cx- Staph, but no AFB or fungi

Verrucus vulgaris (plantar warts)
Keys: wt bearing parts of feet, verrucous appearance, disruption of nl skin lines

Pt with:
Pain with walking
Multiple raised verrucous growths on the heels and balls of the feet that obscure the nl skin markings and are painful when palpated

Condyloma accuminata
Confused with condyloma lata of syphilis (flat, wet, not verrucous)

Sexually active pt with:
multiple painless, cauliflower-like, verrucous lesions on the external genitalia

Molluscum contagiosum
Key- central umbilication
Have depressed center to the lesions
Can be large, numerous with HIV

Pt with:
Multiple, painless clustered papules with central umbilication on the arm (or anywhere else)

Tinea capitis
Keys: elderly, African American, barber, black dots. Usually an unclean razor

African American male, complains of hair loss after getting his hair cut by an electric razor
Annular scaly patch of hair loss
Small black dots over the hair follicles
Palpable small posterior cervical lymph nodes

Tinea corporis
Clues: cat. Could be wrestler.
Often confused with herald patch of pityriasis, but that doesn't itch. Granuloma annulare doesn't scale. Nummular eczema looks different on micro

Pt with:
annular scaly rash on arm, present since week after getting a new cat
Clear towards center of rash with raised advancing erythematous margin and scale

Tinea pedis
Can also see vesicles, nail thickening

Pt wears heavy shoes and goes to then gym with:
Itchy rash between toes
Multiple intensely pruritic pinpoint vesicles between the toes

Tinea versicolor
Patches tend to be worse in the summer
Disseminated skin rashes can be syphilis, micro gives diagnosis
From malassezia furfur; very difficult to tx.

Dark skinned individual presents with:
Scaly rash on chest
Numerous hypo and hyper pigmented areas
No large isolated patch
No itching
KOH stain- spaghetti and meatball fungal hyphae

Pediculosis capitus= head lice
Might see nits, louse picture

Adolescent from a group home with:
Scalp itching
Erythema at the base of the scalp
Mild bilateral posterior auricular lymphadenopathy
Woods lamp- small area of pale blue fluorescence at the base of multiple hair shafts

Pediculosis pubis = pubic lice
Blue macules not always present
Can be visible
Ddx scabies- see itching in other parts of the body as well

Young sexually active adult with:
Itching in pubic region
Multiple small bluish macules along the upper abdomen and inner thighs
Palpable small inguinal lymph node

Scabies
May describe mite burrow
Intense itching, ESP axillary and interdigital webs

Nursing home pt with:
Itching, worse at night, x1 month
Multiple excoriations in both axilla and groin, on the wrists, between fingers

Basal cell CA
Key: pearly papules. May ulcerate

Middle aged Caucasian woman with:
Skin lesion on forehead
HO extensive sun exposure as child with repeated sunburns
Flesh colored papular lesion with pearly sheen, multiple telangiectasias

Multiple actinic keratosis with squamous cell CA in situ
AKs turn into SCC

Middle aged Caucasian woman with:
Skin lesion on forehead
HO extensive sun exposure as child with ,multiple sunburns
Multiple rough scaly patches on forehead, dorsum of hands
One patch on the forehead has a firm hyperkeratotic macule

Melanoma
Remember the ABCDEs

Middle aged Caucasian woman with
Skin lesion on her thigh
HO extensive sun exposure as a child with repeated sunburns
Flat, asymmetric, pigmented lesion, lacks uniform color, is 8mm in size
Enlargement over the last few months

Porphyria cutanea tarda
Always think of with Hep C, isolated rash on hands
Urine uroporprin levels just confirm it
Can be scaly, blistering, vesicles

Pt with Hep C, cirrhosis with:
Blistering lesions on dorsum of hands, began as erythematous macules with adherent scale
Intermittent sun exposure in past month
Elevated urine uroporphyrin levels

Bullous pemphigoid
Usually biopsy
Increasing in frequency
Onset middle ages, pruritic bullae, improves with steroids
Ddx- dermatitis herpetiformis- not restricted to flexural areas, presents with assc disease like celiac dz

Middle aged male, itchy recurrent skin rash
Pruritic papulosquamous lesions in axilla, progress to vesicles and bulla
Vesicles burst, giving erosions
Lesions not symmetric, don't always occur in the same place
Normal mucosal surfaces
Improved with potent topical corticosteroids

Erythema multiforme with genital HSV
Usually assc with new HSV infection, can also see with mycoplasma infection

Sexually active adult with:
Pain in the genital region
Rash on forearm
Multiple small painful blisters on external genitalia with surrounding erythema
Several small target shaped lesions on forearm without scale or itch
No mucosal lesions

Stevens-Johnson syndrome
Triggers: sulfas, abxs, allopurinol, antiepileptics (esp phenytoin, carbamazapine), NSAIDs
Skin sloughing of >30%= toxic epidermal necrolysis

Pt with HIV:
prescribed Bactrim for presumed pneumocystis infection
2 days later, gets fever, painful erythematous blistering rash on <10% of body surface, including mucous membranes, mouth, and conjunctiva

Pityriasis rosea

Young patient with:
Asymtomatic rash on back 1 wk after circular salmon-colored scaly patch on chest
Multiple plaques on back with long axis oriented in direction of skin lines in "christmas tree" distribution; No tx necessary and usually clears within 6-8 wks.

Acanthosis nigricans
Can see with DM, new GI or lung malignancies that are aggressive and quickly spreading

Obese pt with:
Polyuria
Velvety pigmented rash in folds of neck and axilla
Fasting glucose >125

Necrobiosis lipoidica diabeticorum
Painful nodules would be E. Nodosa. These are yellow plaques

Diabetic pt with:
Yellowish irregular plaques with purplish pigment at the edges over both shins

This is seborrheic keratoses and it may be a marker for a non-skin malignancy but is completely benign and not a precancerous lesion. Usually has "stuck on" appearance (like you stuck on a piece of clay) with warty surface.

What's this and is it a marker for malignancy.

Guttate psoriasis. Get small, droplike 1-10mm salmon-pink papules with fine scale. Guttate comes fro latin "gutta" which means drop. History of URI may precede eruption, esp due to strep;

22 y/o woman presents with hundreds of 2-5 mm scaly red papules on trunk and extremities that are moderately pruritic. Lesions appeared abruptly about 2 wks prior to exam and quickly spread. Pt had sore throat the prior month. What's dx?

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